What is the CVSS score of CVE-2026-49237?

CVE-2026-49237 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.0%.

Which versions of Canonical Multipass are affected by CVE-2026-49237?

Canonical Multipass for macOS (versions before 1.16.3) contains a local privilege escalation vulnerability allowing local users to gain root-level access by replacing auxiliary binaries.. A patch is available.

How to fix or mitigate CVE-2026-49237?

Within 24 hours: Identify and inventory all macOS systems running affected Multipass versions (prior to 1.16.3); restrict non-essential local user account access on affected systems. Within 7 days: Implement restrictive PATH configuration on multipassd LaunchDaemon processes to block binary planting; enable enhanced audit logging for privilege escalation attempts. Within 30 days: Monitor Canonical's official advisories for patch release; develop contingency plans including workload migration if patch delivery extends beyond organizational risk tolerance.

Canonical Multipass CVE-2026-49237

EUVD-2026-32900 HIGH

Incorrect Default Permissions (CWE-276)

2026-05-28 security@ubuntu.com

Privilege Escalation Apple Canonical

7.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.8 HIGH

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Patch available

May 28, 2026 - 15:01 EUVD

Analysis Generated

May 28, 2026 - 14:31 vuln.today

CVE Published

May 28, 2026 - 14:16 nvd

HIGH 7.8

DescriptionCVE.org

An issue was discovered in Canonical Multipass for macOS before version 1.16.3 due to an incomplete fix for CVE-2025-5199. While the patch in version 1.16.0 updated the ownership of the multipassd daemon binary to root:wheel, five co-located binaries (multipass, qemu-img, qemu-system-aarch64, qemu-system-x86_64, and sshfs_server) in /Library/Application Support/com.canonical.multipass/bin/ retain ownership by the installing user and remain writable. Because the root LaunchDaemon (com.canonical.multipassd.plist) configures a PATH environment variable that prioritizes this user-writable directory and invokes these auxiliary binaries by their bare names, a local attacker can replace an auxiliary binary (such as qemu-img) with a malicious wrapper. When the root daemon subsequently triggers the binary during routine execution (e.g., via multipass launch), the malicious code executes with root privileges, leading to local privilege escalation.

AnalysisAI

Local privilege escalation in Canonical Multipass for macOS before 1.16.3 allows a low-privileged local user to obtain root execution by replacing co-located auxiliary binaries that the multipassd LaunchDaemon invokes via a user-writable PATH directory. The flaw is an incomplete remediation of CVE-2025-5199: while 1.16.0 corrected ownership of the multipassd binary itself, five sibling binaries (multipass, qemu-img, qemu-system-aarch64, qemu-system-x86_64, sshfs_server) were left owned by the installing user and writable, enabling binary planting. No public exploit identified at time of analysis, and the issue is not currently listed in CISA KEV.

Technical ContextAI

Multipass is Canonical's lightweight VM manager for macOS that ships a privileged LaunchDaemon (com.canonical.multipassd.plist) which manages QEMU-backed Ubuntu instances. The root daemon's plist defines a PATH environment that prioritizes /Library/Application Support/com.canonical.multipass/bin/ and invokes helper utilities (qemu-img, qemu-system-*, sshfs_server, multipass) by bare name rather than absolute path, so resolution of those names depends on directory contents and ownership. The root cause is CWE-276 (Incorrect Default Permissions): the installer left auxiliary executables owned and writable by the unprivileged installing user, so any code substituted at those paths is later loaded by a root-owned process - a classic write-where-root-reads trust boundary violation that the 1.16.0 fix only partially addressed by changing ownership of the daemon binary alone.

RemediationAI

Vendor-released patch: upgrade Canonical Multipass on macOS to version 1.16.3 or later, which is referenced as the fixed release in the GitHub Security Advisory at https://github.com/canonical/multipass/security/advisories/GHSA-r2xg-x32f-23c5. Until the upgrade is deployed, administrators can apply compensating controls by recursively changing ownership of /Library/Application Support/com.canonical.multipass/bin/ and its contents to root:wheel with mode 0755 so the installing user can no longer overwrite the auxiliary binaries (side effect: subsequent Multipass auto-updates or reinstalls performed under the user account may fail or revert permissions), and by unloading the LaunchDaemon with launchctl unload /Library/LaunchDaemons/com.canonical.multipassd.plist on systems where Multipass is not actively required (side effect: VM management via Multipass is disabled until reloaded). On multi-user macOS hosts, restrict interactive login to trusted accounts to reduce the local-attacker prerequisite.